Prevalence of acute deep vein thrombosis according to HIV status following major orthopaedic surgery at the University Teaching Hospital, Lusaka, Zambia

Abstract

Background: Hypercoagulable states and immobilization following lower limb, pelvic, and spinal surgery increases the risk of deep vein thrombosis (DVT). It is also suggested that HIV alone increases the risk of deep vein thrombosis. However no study has been done to determine the prevalence of deep vein thrombosis in HIV seropositive individuals who have undergone lower limb orthopaedic surgery in the Zambian context. We therefore conducted this study to determine the prevalence of deep vein thrombosis in patients who are HIV seropositive in comparison to those who are HIV seronegative after undergoing lower limb orthopaedic surgery. 

Methods: A total of 42 Patients were enrolled. Of these 23 (54 %) were HIV negative controls and 19 (46 %) were HIV positive patients who underwent lower limb surgery or spinal surgery. Demographic and HIV status data was collected prior to surgery. After surgery a blood sample was tested for fibrinogen degradation products (D-dimer) levels. The patients were then monitored for the development of clinical DVT and those that developed clinical DVT had an ultrasound to confirm the diagnosis. 

Results: The majority (81%) of the study population were under the age of 50 years. The mean values of D-dimers were 2.33 ± 1.65 μg/ml for the HIV negative group and 2.55 ±1.50 μg/ml for the HIV positive group. The number of positive D-dimer results was similar in the two groups, 94.7% for the HIV cohort and 95.7% in the negative group (X 2 0.19 p=0.89). There was a positive correlation between the D-dimer value and the type of surgery done in both the HIV positive group (R 0.390 p = 0.049) and the HIV negative group (R 0.398 at p = 0.03). In both group’s hip and knee surgeries gave higher values of D-dimers. There was no statistical difference in the occurrence of a positive D-dimer and CD4 count (X2 0.95 p=0.89). The combined prevalence of clinical DVT confirmed by compression ultrasonography in the entire study population was 4.8%. The prevalence in the HIV seropositive group and HIV seronegative groups were 5.3% and 4.3% respectively (X2 0.19 p= 0.89). None of the patients received preoperative DVT prophylaxis due to cost but both patients that developed DVT received antithrombotic treatment. 

Conclusions: There was no significant difference in the prevalence of DVT between patients who were HIV seronegative and seronegative following major lower limb and spinal orthopaedic surgery. Both groups had raised D-dimer values. 

Keywords: deep vein thrombosis; HIV; D-dimer; Doppler ultrasound